Cobalt Alloy 12 Bushing for Valve

STP 12 is a cobalt-based alloy known for its excellent wear resistance, high-temperature performance, and corrosion resistance. It is often used in applications where parts must withstand extreme conditions, such as in the oil and gas industry, where it is commonly used for valve components. Typically, it will be used together with cobalt alloy grade 6 bushing. If you want to know more, there may be some reason in the blog why you should use STP 6 and STP 12 as a pair of bushes simultaneously.

By using both alloys in a valve, you can take advantage of the unique properties of each alloy. For example, STP 6 might be used in areas of the valve subjected to high impacts or shock loadings, such as in the valve seat or disc. STP 12, on the other hand, might be used in areas of the valve subjected to high-temperature or abrasive conditions, such as in the valve stem or guide.

The cobalt alloy bushings are available in different grades with different hardness, as follows:

Cobalt alloy chemical composition

• STP 1  C: 2.2～2.8%, Mn: -, Si: ≤2.0%, Cr: 29.0～33.0%, Ni: ≤3.0%, Mo: ≤1.0%,  W: 11.0～14.0%, Co: Bal., Fe: ≤3%
• STP 3  C: 2.0～2.7%, Mn: ≤1.0%, Si: ≤1.0%, Cr: 29.0～33.0%, Ni: ≤3.0%, Mo: -,  W: 11.0～14.0%, Co: Bal., Fe: ≤3%
• STP 4  C: 0.8～1.3%, Mn: ≤1.0%, Si: ≤1.5%, Cr: 28.0～32.0%, Ni: ≤3.0%, Mo: ≤1.5%,  W: 12.5～15.5%, Co: Bal., Fe: ≤3%
• STP 6  C: 0.9～1.4%, Mn: ≤1.0%, Si: ≤1.5%, Cr: 27.0～31.0%, Ni: ≤3.0%, Mo: ≤1.5%,  W: 3.5～5.5%, Co: Bal., Fe: ≤3%
• STP 12  C: 1.1～1.7%, Mn: ≤1.0%, Si: ≤1.0%, Cr: 28.0～32.0%, Ni: ≤3.0%, Mo: -,  W: 7.0～9.5%, Co: Bal., Fe: ≤3%
• STP 19  C: 1.5-2.0%, Mn: ≤1.0%, Si: ≤1.0%, Cr: 29.5～32.5%, Ni: ≤3.0%, Mo: -,  W: 9.5～11.5%, Co: Bal., Fe: ≤3%
• STP 20  C: 2.2～3.0%, Mn: -, Si: ≤2.0%, Cr: 25.0～29.0%, Ni: ≤3.0%, Mo: ≤1.0%,  W: 14.0～19.0%, Co: Bal., Fe: ≤3%

Cobalt Alloy bushing can be used for many industries, such as oil & gas pumps, galvanized production lines, etc, with its excellent wear and corrosion resistance if the user environment needs the parts to have high temperature, wear, and corrosion resistance simultaneously. STP 6 bushing is also a good part of the butterfly valve. We have produced thousands of specifications for the STP 6 bush, all based on the customer’s drawing. This is one of our mature products. Quality can be guaranteed.

Now, we can supply many kinds of cobalt alloy bushing, such as STP 3, STP 4, STP 6, STP 12, etc. If you need other cobalt alloy products, we can supply many rods, plates, blades, saw teeth, STP valve seats, valve balls, etc.

We are happy to supply samples for your test. Please leave an inquiry if you are interested.